Composite material

ABSTRACT

Composite material ( 10 ) comprises a substrate ( 1 ) and a chemically, mechanically, physically, catalytically and/or optically functional titanium oxide layer ( 2 ), applied on at least one side thereof. A titanium oxide layer ( 2 ) is deposited on the substrate ( 1 ) as a base layer ( 3 ), made from TiO x  with an oxygen content of 0.7≦x&lt;2, or made from TiO x (OH) y  with an oxygen content of 0.5≦x&lt;2 and a hydroxide content of 0≦y&lt;0.7 and an upper layer ( 4 ) of amorphous and/or crystalline TiO 2  applied to said base layer ( 3 ). In a first method variation, firstly a base layer ( 3 ) of TiO x  with an oxygen content of 0.7≦x&lt;2 is reactively or non-reactively deposited, then, through an increase in the oxygen content, the process pressure, the capacity and/or the substrate temperature, an upper layer ( 4 ) of amorphous and/or crystalline TiO 2  is deposited. In a second method variation, firstly a base layer ( 3 ) of TiO x  with an oxygen content of 0.7≦x≦2 is reactively or non-reactively deposited and then post-oxidized on the surface by means of an electrochemical, thermal and/or plasma process, until the base layer ( 3 ) is converted into amorphous or crystalline TiO 2  at least partly in an upper layer ( 4 ).

CROSS REFERENCE TO RELATED PATENT APPLICATIONS

This application is a divisional of U.S. Ser. No. 10/529,775, filed Mar.30, 2005, which is a national stage application of PCT/CH2003/000653,filed Sep. 30, 2003, which claims priority of Swiss application No.1630/02, filed Sep. 30, 2002. The disclosures of these applications areincorporated by reference in their entireties.

FIELD AND BACKGROUND OF THE INVENTION

The invention relates to a composite material of a substrate with,applied to at least one side, a titanium oxide layer with a chemical,physical, mechanical, catalytic and/or optical function. The inventionfurther relates to a process for the production and uses of thecomposite material.

The broad term substrate comprises firstly easily flammable and/orheat-sensitive materials of polymers, polymer-like or natural materials,but also materials of metal, glass, ceramic and combinations thereof(composites), for which a coating process at low temperatures ispreferred for process technical reasons. The substrates are coated withceramic titanium oxide layers which fulfill one or more protectiveeffects and for example thus increase safety in everyday dealings withhighly flammable and/or easily contaminated materials.

The burning behaviour of materials (in particular textiles, films andplastic containers) and the assessment of their fire risk is of greatimportance as they are always present in the human environment. Textilesare used for example in a multiplicity of applications mainly asclothing, domestic textiles and technical textiles. The combustionprocess is initiated by way of heating, decomposition and combustion ofthe flammable material. Depending on its composition, under the effectof heat the material will first melt, flow or remain unchanged, and onfurther supply of energy will finally decompose and hence develop heat.After ignition of the flammable material the flames are propagated byway of its decomposed surface, where the speed of flame propagation isaccompanied by heat emission from the material. As well ascombustibility therefore flame propagation and the degree of heatemission are parameters which determine fire.

The required flame protection can be achieved traditionally in variousways. Firstly intrinsically flame-protected polymers can be used such aspolyvinyl chloride (PVC) or fluoropolymers. Combustible polymers such aspolyethylene (PE), polypropylene (PP) or polyamide (PA) can be givenvarious flame-inhibiting additives (e.g. aluminium hydroxide, magnesiumhydroxide, organic bromine compounds). Usually however a high proportionof these additives in the polymer matrix is required to achieve adequateflame protection. This is expressed in a high density, loss offlexibility and low mechanical properties of the material.

Titanium dioxide (TiO₂) has known properties as a photo-semiconductor, ahigh refractive index, a high transparency in the visible andnear-infrared wavelength range, a high dielectric constant, gives verygood wear protection, is chemically inert and finally has excellentthermal properties. TiO₂ crystallises in three modifications: tetragonalrutile, anatase and orthorhombic brookite. Special experimentalconditions are required to be able to produce brookite. Rutile isinteresting for optical applications while the photo-catalyticproperties of anatase are more pronounced due to the optical band gap at3.2 eV.

There are numerous sub-oxides of titanium (TiO_(x)) with an oxygencontent of 0.7≦x≦2. TiO_(x) with an oxygen content of 0.7≦x≦1.5 at roomtemperature has an electrical resistance of around 400 μΩcm, at a higheroxygen content this increases rapidly, and TiO₂ is an insulator.

It is known that with TiO₂ layers, the crystallinity and itsmodifications depend on the production method, process parameters andcoating configuration. Usually crystalline TiO₂ layers are produced withsol-gel processes, spray pyrolysis, painting, electron beam vaporisationon metal-organic chemical vapour deposition (MOCVD) above 300° C. TiO₂layers which are produced with reactive vaporisation or plasma-activatedchemical vapour deposition methods (PACVD) below 300° C. are usuallyamorphous and less dense. If these amorphous layers are tempered between300° and 500° C., the anatase structure of TiO₂ is dominant; on heattreatment above 600° C., the TiO₂ modification rutile forms.

Secondly, amorphous or crystalline TiO_(x) or TiO₂ layers can begenerated below 300° C. with methods which are characterised by a higherparticle energy—e.g., reactive or non-reactive magnetron sputtering(cathode sputtering), non-filtered or filtered spark discharge,ion-beam-assisted deposition (IAD) and pulsed laser deposition. With RFsputtering, depending on the choice of coating parameters, TiO₂ can bedeposited amorphous or crystalline on an unheated material. In SURFACEAND COATINGS TECHNOLOGY 102 (1998), 67-72, thin titanium dioxide layersare described which are deposited by RF sputtering in an argon-oxygenatmosphere. The microstructures of the TiO₂ deposition vary within abroad range from compact to porous and columnar. The O/Ti ratio rises asthe pressure increases when the other reaction parameters remainunchanged. The publication deals primarily with scientific experiments.

SUMMARY OF THE INVENTION

The invention is based on the object of creating a composite materialand a process for its production with a functional titanium oxide layerof the type cited initially which brings improved, in particularsynergetic functionalities for a wide range of substrates. Aninteraction of oxygen and other reactive gases with the substrate shouldbe prevented and said substrate isolated thermally.

With relation to the composite material, the object according to theinvention is achieved in that on the substrate is deposited a titaniumoxide layer of a base layer of TiO_(x) with an oxygen content of 0.7≦x<2or TiO_(x)(OH)_(y) with an oxygen content of 0.5≦x<2 and a hydroxidecontent of 0≦y<0.5 and on this base layer is applied a top layer ofamorphous and/or crystalline TiO₂. Special and refined embodiments ofthe composite material are the subject of dependent claims.

The substrate with a base layer and a top layer, where applicable alsowith further layers, is referred to here and in general for the sake ofsimplicity as a composite material. Furthermore to avoid repetition, theterm TiO_(x) also always includes the variants TiO_(x)(OH)_(y). Theterms TiO_(x), TiO_(x)(OH)_(y) and TiO₂ comprise pure titanium oxidelayers but also titanium oxide layers with other metal oxides where thebase layer as a whole contains less than 50 w. %, the top layer is as awhole less than 7 w. % of other metal oxides listed in detail below.

The titanium oxide layer according to the invention is amulti-functional layer which protects a substrate e.g., from combustion,contamination, degradation (migration of additives, photo-oxidization).This allows any material to be given flame protection, a hygienicprotection (self-cleaning, germicidal effect), anti-static protectionand/or an anti-fogging effect. Such a composite material is suitable forexample for use in the medical sector, for household accessories,domestic articles, textiles, carpets, cables and photovoltaics, and incleaning plants for water, watery solutions and air.

Suitable materials to be protected are in particular highly flammableand/or heat-sensitive materials such as polymers, low melting metals,composites and natural substances in the form of rigid to flexiblefilms, fabrics, membranes, fibres, tubes, plates, containers andpowders.

The titanium oxide layer preferably has a total layer thickness of 3 to1000 nm, where the top layer comprises at least around 10% of the totallayer thickness. The top layer comprises titanium dioxide, TiO₂, inpractice however the transition is flowing and a value of TiO_(1.99) forexample can be allocated to the top layer. Furthermore in practiceultra-thin layers of just 3 nm occur rather rarely, suitably the entirelayer thickness is in the range of 10 to 300 nm, in particular 20 to 150nm, where 10 to 50% of the entire layer thickness consists of the toplayer.

On use of substrates of plastic and natural substances (in particularwool and cotton), a titanium dioxide layer can be problematical, it canalso as a catalyst triggering a decomposition of the substrate surface.With plastics and natural substances it may be suitable, beforeapplication of the base layer of TiO_(x), to apply a protective layer ofat least one metal oxide of the group which preferably comprises MgO,ZnO, ZrO₂, In₂O₃, Sb₂O₃, Al₂O₃ and SiO₂, and/or a polar adhesion layeras an adhesion-promotion layer. The choice of optimum metal oxide oroptimum mixture of metal oxides can easily be determined by thespecialist by experiment. For a base layer of TiO_(x) with an oxygencontent x<1.9 and/or a significant hydroxide content of 0.2≦y<0.7, thereis usually no danger for the substrate.

In a further variant of the titanium oxide layer, between the base layerand the top layer can be deposited an electrically conductiveintermediate layer which preferably comprises TiO_(x) with an oxygencontent of 0.5≦x<1.5. The electrical conductivity diminishes above anoxygen content of x >1.5. The layer can no longer be regarded aselectrically conductive, a top layer of TiO₂ with an oxygen content ofx=2 is an insulator. Clearly, an electrically conductive intermediatelayer can be deposited in particular when the oxygen content of the baselayer lies above x=1.5 and if an anti-static effect is to be achieved.

As will be explained in more detail later, at least the top nine atomiclayers of the top layer mainly comprise the crystalline TiO_(x)modification anatase, which corresponds to a layer thickness of around 3nm.

When the multi-functional titanium oxide layer is used as a flameprotection layer of a plastic substrate, sub-micron filler particles ofa metal oxide can be added, for example TiO_(x) and/or Sb₂O₃, or a metalhydroxide which dehydrates under heat, for example Al(OH)₃ and/orSb(OH)₃. In this case the TiO_(x) base layer suitably has an oxygencontent of 1.5≦x≦1.9.

In relation to the process for deposition on a substrate of a titaniumoxide layer with a chemical, physical, mechanical, catalytic and/oroptical function, the object according to the invention is achieved in afirst variant in that first is deposited a reactive base layer ofTiO_(x) with an oxygen content of 0.7≦x<2, then by increasing the oxygencontent, process pressure, power and/or substrate temperature a toplayer of an amorphous or crystalline TiO₂ is deposited.

In the second variant the object is achieved in relation to the processfor depositing on a substrate a titanium oxide layer with a chemical,physical, mechanical, catalytic and/or optical function in that firstreactively or non-reactively a base layer is deposited of TiO_(x) withan oxygen content of 0.7≦x<2 and then electrochemically, thermallyand/or with a plasma process the surface is post-oxidized until the baselayer is restructured at least partly into a top layer of amorphous orcrystalline TiO₂.

After both processes a top layer of TiO₂ is produced. The processparameters are set so that the top layer usually constitutes at least 10% of the total layer thickness.

For extremely thin layers according to the second variant the entirebase layer can be restructured into a TiO₂ layer, but this is notusually the case.

The application takes place with the methods which are known inthemselves and already mentioned above, for process technical reasonscoating processes at low temperatures are preferred. Any intermediatelayer between the base and cover layer and a protective layer betweenthe substrate and the base layer are also deposited using one of thesaid methods.

Preferably, in particular with a plastic substrate or non-polarmaterial, the base layer or protective layer is applied after plasmaactivation of the substrate surface. This increases the adhesion of thelayer to be deposited. Pretreatment can also take place by means of anultra-thin polar plasma layer of a few nanometres thickness. This polarplasma layer firstly increases the adhesion of the base layer andsecondly prevents degradation of the substrate. For the generation of apolar layer with long-term stability, reference is made to WO 99/39842,according to which for polar coating a water-free process gas is usedwhich contains at least one also substituted hydrocarbon compound withup to 8 C/atoms and an inorganic gas.

The ceramic coating can take place directly after the surface treatmentof the substrate or later.

In a refinement of the process a base layer of TiO_(x) mixed with atleast one metal oxide can be deposited. Suitable metal oxides are forexample MgO, ZnO, ZrO₂, In₂O₃, Sb₂O₃, Al₂O₃ and/or SiO₂, where theproportion of TiO_(x) after mixing remains above 50 w. %. Furthermore,the top layer of TiO₂ can also be doped with Fe₂O₃, WO₃, MnO₂, NiO, BaOand/or CaO, where the proportion of TiO₂ after doping remains above 93w. %. If metal oxides of both groups are added to the base layer ofTiO_(x), the total proportion of all metal oxides must remain below 50w. %, the proportion of the added doping metal oxides of the secondgroup must remain below 7 w. %.

The deposition according to the invention of a base layer of TiO_(x)(0.7≦x<2) and a top layer of TiO₂ brings numerous advantages listedinexhaustively below:

-   -   The process can be performed at a substrate temperature of        ≦200° C. which is important in particular for polymer        substrates. Also a low temperature process may be indicated for        metals, ceramics and composites and combinations thereof.    -   Deposition of an electrically conductive TiO_(x), layer onto        electrically non-conductive substrates reduces the electrostatic        charge and thus supports the hygiene protection synergetically.    -   The coating of an organic chemical substrate (polymer, natural        substance) with a base layer of TiO_(x) (x<1.9) and/or        TiO_(x)(OH)_(y) with a significant hydroxide proportion is        usually non-problematical (no degradation).    -   A thin coating has the advantage that the mechanical and        processing properties of the substrate are retained. This is        particularly important for the processing of fibres and films        which must subsequently withstand further treatment processes.    -   With a plasma-activated process, prespecified layer properties        such as porosity, crystallinity, density, electrical        conductivity, refractive index and polarity can be produced in a        targeted manner. In particular, the combination of dense with        porous nano-structured multilayers which can have different        electrical conductivity and refractive indices, can achieve a        synergetic functionality of the titanium oxide layer. For        example, the topography of the substrate can be changed or        supplemented with suitable layer topography such that this        synergetically reinforces the cleaning and hygiene functions.    -   The synergetic multi-functionality of the titanium oxide layers        can be adapted to the application concerned. The        plasma-activated low temperature process preferred for        production of the layer systems e.g. by magnetron sputtering,        spark discharge and plasma MOCVD, are particularly suitable for        varying the stoichiometry and layer structure by means of simple        process management, and for stabilising the modification anatase        by means of the doping of a titanium oxide layer with at least        one metal oxide, for example Fe₂O₃, which is easy to perform        process technologically. Low temperature processes are therefore        also interesting for materials which are not sensitive to heat,        such as glass. Thanks to a titanium oxide layer according to the        invention with a base layer of        TiO_(x) and a top layer of TiO₂ which has a thickness of >3 nm,        in particular >10 nm, hygiene protection, biocompatibility,        anti-fogging effect and hence active flame protection can be        achieved on practically all substrates. Thanks to the underlying        TiO_(x) base layer biocompatibility, degradation protection of        the substrate, passive flame protection, anti-static effect,        migration and diffusion barrier protection are also guaranteed.

A photocatalytically active hygiene protection layer of TiO₂ has theability, in damp atmospheres and under daylight or UV radiation, todecompose various organic compounds on the surface (compounds containingcarbon and/or nitrogen, such as oil, bacteria). Thanks to the reductionin contact angle between water and the TiO₂ surface of the top layer,the result is also an anti-fogging effect and a supported removal ofdust particles. This hygiene protection, also known as a self-cleaningeffect, synergetically reinforces the passive flame protection of aflammable substrate. In this case there is active and reactive flameprotection.

In passive flame protection the direct contact of the atmosphere withhighly flammable substrate is reduced by the coating according to theinvention with a thermally stable titanium oxide which on fire forms acrust of heated titanium oxide. The speed of flame propagation isreduced by the crust and the development of gases escaping from thesubstrate is reduced (diffusion barrier), which finally can lead toextinction of the flame by passive protection.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in more detail with reference to embodimentexamples shown in the drawing which also the subject of dependentclaims. The mostly partial cross sections depict diagrammatically:

FIG. 1 a film-like composite material with a titanium oxide layerdeposited on one side, FIG. 2 a variant according to FIG. 1 with a twopart titanium oxide layer, FIG. 3 a variant of FIG. 2 with a titaniumoxide layer deposited on both sides, FIG. 4 a fibre with a three parttitanium oxide layer, and FIG. 5 a variant according to FIG. 2 with anadditional protective layer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a composite material 10 with a substrate 1 and applied onone side a titanium oxide layer 2 without further specification. FIG. 1corresponds to the usual prior art, a titanium layer 2 is applied to asubstrate 1 where it fulfills a protective or other function. FIG. 1however shows also a special case of the present invention. A thinTiO_(x) layer has been applied which is post-oxidized into TiO₂. Becauseof the extremely thin layer, the TiO_(x) layer has been oxidized overthe entire thickness into TiO₂. The substrate 1 which is shown merelypartially can, e.g., be a film, fabric, membrane, plate, fibre, tube,cable or container part and comprise a conventional material.

In FIG. 2 the titanium oxide layer 2 is divided into a base layer 3 ofTiO_(x) where the oxygen content is 0.7≦x<2, and a top layer 4 of TiO₂.Distributed finely dispersed in the substrate 1 are submicron particles6 of a metal oxide/metal hydroxide. The top layer 4 of TiO₂ is mainlypresent in the tetragonal crystal structure anatase.

The transition from the base layer 3 to the top layer 4 is shownsharply. If the base layer 3 is partly converted into a top layer 4 bymeans of post-oxidization, the transition is flowing.

FIG. 3 shows a composite material 10 with titanium oxide layer 2 appliedto both sides. The structure of this titanium oxide layer 2 correspondsto that in FIG. 2.

In FIG. 4 the substrate 1 is a textile fibre and deposited directly onthe base layer 3 is an electrically conductive intermediate layer 5which surrounds as a cylinder casing the base layer 3 which is depositeddirectly on the fibre. This electrically conductive intermediate layer 5comprises TiO_(x) and has an oxygen content of 0.7≦x<1.5. Above theintermediate layer lies the top layer 4 which is also formed as acylinder casing.

Certain plastic substrates are decomposed at least superficially bytitanium oxide layers. In the embodiment according to FIG. 5 therefore aprotective layer 7 is deposited directly on the substrate 1, where thisprotective layer 7 has a thickness also lying in the nanometre range.This protective layer 7 is also applied on both sides consists of atleast one metal oxide, preferably of the group ZnO, MgO, ZrO₂, In₂O₃,Sb₂O₃, Al₂O₃ and/or SiO₂, or a polar adhesion layer, for example, apolar plasma layer which also ensures good adhesion to the substrate 1.

Table 1

The coating techniques and process parameters are adapted to therequirements for the product to be produced or substrate to be coated.Table 1 shows the production of selected functional titanium oxidelayers and their protective and/or function effect. In the base layer 3a relatively high content of hydrogen was analysed with ERDA (ElasticRecoil Detection Analysis), which is bonded in the layer in the form ofhydroxide ions and depends on the process parameters and substratetemperature.

Composite materials which are coated on both sides were each given thesame coating. During the coating process the substrate temperature is≦200° C. The anti-fogging effect is observed at a surface tension of >50mN/m and a correspondingly smooth surface. The surface tension alsodepends on the process parameters in production of the layer.

The thermal capacity of the fabric-like substrate which is coatedincreases virtually linear with the increasing layer thickness.According to the coated surface, the effect is visibly greater for PETfilm than for PET fabric. The thicker fabric mixture comprising 36%polyester and 64% viscose C shows a far less pronounced effect than thefine PET fabric. It is clear from this data that the layer thicknessmust be adapted to the substrate concerned (material, texture,thickness) in order to achieve the desired effect.

The average flame propagation speed for general textiles should be lessthan 90 mm/s, for textile curtains less than 60 mm/s. Even with a 12 nmthin ceramic coating, for a fine PET fabric the flame propagation speedlies far below the limit value of 60 mm/s and at a layer thickness of180 nm achieves a value of 31 mm/s. For the viscose/polyester mixturethere is a significant reduction from 142 to 115 mm/s with a 95 nm thickTiO_(x)/TiO₂ layer. TABLE 1 Examples of processes for production ofselected ceramic metal oxide layers with multiple protective or functioneffects Process P₍₀₂₎/ Stoichi- Layer Power pressure P_((lot)) Thicknessometry, Substrate Process [W] [μbar] [%] [nm] structure ^(a) A reactiveDC sputtering 2000 10 15 12/180 TiO_(1.9) of Ti(s) + O₂ plasmapost-oxidation 800 200 90 TiO₂ PET fabric 85 μm thick substrate 2 × 12PET fabric 85 μm thick substrate  2 × 180 B reactive DC sputtering 800 710 360 TiO_(1.7)(OH)_(0.4) of Ti(s) + O₂ reactive DC sputtering 1000 127.5 75 TiO_(0.9) of Ti(s) + O₂ reactive DC sputtering 1000 20 25 20 TiO₂of Ti(s) + O₂ C reactive RF sputtering 600 15 7.5 70 TiO_(21.9) ofTi(s) + O₂ reactive RF sputtering 1000 23 70 25 TiO₂ of Ti(s) + O₂ PETfabric 85 μm thick substrate 2 × 95 PET film 12 μm thick substrate 2 ×95 Viscose/PET 64%/36% mixture 2 × 95 D RF sputtering of MgO 1500 15 080 MgO RF sputtering of TiO(s) 700 20 0 15 TiO_(1.0) RF sputtering ofTiO₂(s) 1000 20 0 5 TiO₂ PET fabric 85 μm thick substrate  2 × 100 PETfilm 12 μm thick substrate  1 × 100 E Plasma MO-CVD with 1900 1000 30 40TiO_(1.9) Ti(O—CH(CH₃)₂)₄ Plasma MO-CVD with 2700 2000 60 350 TiO₂Ti(O—CH(CH₃)₂)₄) and FE(C₅H₇)₂)₃) PET film 12 μm thick substrate  1 ×390 Spec. thermal Flame Trans- Layer capacity LOI ^(b) propagationmission ^(e) Comments Substrate Δ [J/gK] [vol %] speed ^(c) [mm/s] BIF^(d) [%] Material layer A Base layer 3 Top layer 4 PET fabric 1.6 5 6.055 — Material layer PET fabric 4.7 10 3.0 31 — B Base layer 3Intermediate layer 5 25 Top layer 4 C Base layer 3 Top layer 4 PETfabric 2.4 8 3.7 44 PET film 4.0 15 — — 93 19 Material layer Viscose/PET1.4 — — 115 D Base layer 3 Intermediate layer 5 Top layer 4 PET fabric3.3 — 20 Material layer PET film 57 E Base layer 3 Top layer 4 PET film120 42 Material layerLegend

a. The stoichiometry of the layers and the layer surface was determinedwith RBS (Rutherford Backscattering Spectroscopy), ERDA (Elastic RecoilDetection Analysis) and XPS (X-ray Photoelectron Spectroscopy). Thecrystal structure of the layers was analysed qualitatively with TEM(Transmission Electron Spectroscopy) and XRD (X-ray). In the mixtures ofamorphous and various crystalline phases (anatase, rutile and suboxidesTiO_(x) (0.5≦x<2) the corresponding phases could be identified in eachcase.

b. The LOI (Limiting Oxygen Index) ISO 4589-2/ASTM D2863-77 describesthe increase in limiting oxygen content in a gas mixture in the vol. %for a flame to combust the coated material.

c. Burning speed, which was performed according to test 4589-2/ASTMD2863-77 (left-hand column) and average flame propagation speed, whichwas performed according to burning test BS EN ISO 6941 (right-handcolumn).

d. The BIF (Barrier Improvement Factor) shows the factor by which theoxygen permeability (measured in [ccm/m².d.bar]) according to ASTM D3985-95 at 0% r.h. and 23° C.) diminishes due to coating of 12 μm thickPET film in comparison with the uncoated PET film (124 cm/ m².d.bar).

e. A coated pre-radiated glass material is immersed in a 0.05 mmolwatery methylene blue solution and irradiated with a UV lamp (2 mW/cm²).The transmission change in solution is measured after 96 hours in aspectrophotometer at a wavelength of 650 nm according to the Sinku-RikoPCC-1.

The electrical conductivity and electrical resistance of theintermediate layer 5 concerned is given in example 3. The electricresistance of a 100 nm thick TiO₂ layer is more than 2.10⁵ Ωcm.

EXAMPLES

Some examples are described below for the production of multifunctionaltitanium oxide layers. In each case the layer properties and the layerstructure are adapted to the product requirements concerned.

Example 1 Reactive Magnetron Sputtering with Subsequent Post-Oxidization

The deposition of a titanium oxide layer 2 on any substrate 1 with areactive sputtering process (DC=(pulsed) direct current; RF=radiofrequency) of titanium with a mixture of process gases of argon andoxygen. Then by a change in plasma conditions (variant 1a) and/or withpost-oxidization (variant 1b) of the composite material a TiO₂ top layer4 containing anatase is formed.

Coating Process:

-   Target: Titanium metal (99.98%)-   10 Power: 1-7 W/cm² DC/RF-   Process pressure: 10 μbar-   Partial pressure P(O₂)/p(tot): 10% DC/RF    Variant 1a: TiO₂ Layer at the End of the Process

In the last phase of the reactive sputtering process, the processpressure is increased to 20 μbar and in the case of the DC sputteringprocess the oxygen partial raised to 30%, in the case of RF sputteringprocess the oxygen partial pressure is raised to 60%. The increase inprocess pressure and oxygen partial pressure acts favourably on thelayer properties of the top layer which are characterised by a lowerdensity, a higher porosity and hence larger surface.

Variant 1b: Post-Oxidization of TiO_(x) to TiO₂

In this case the titanium oxide layer is oxidized in an oxidizingatmosphere with a PE-CVD at low pressure to atmospheric pressure. Thepenetration depth of the post-oxidization depends on the density of theTiO_(x) layer and the process conditions.

-   Power (pulsed/continuous): 50-3000 W radio frequency (MHz),    hyperfrequency (GHz) or low frequency (kHz)-   Process pressure: 0.1 mbar-1 bar-   Partial pressure p(O₂)/p(tot): 50-100%

Example 2 Adhesion-Promoting Pretreatment and Plasma-Activated MOCVDProcess

Plasma activation of a substrate take place (1) to increase the adhesionof the coating.

Pretreatment:

-   Power (pulsed/continuous): 200-1500 W hyperfrequency (2.45 GHz)-   Process pressure: 20 μbar-1 bar-   Partial pressure p(O₂/N₂O)/p(tot): 20-80%    Base Layer 4 Comprising TiO_(x) or TiO_(x) Mixed with SiO_(x):

Then introduced into the reaction chamber is a titanium-containingmonomer gas for example titanium tetrakis-isopropoxide (TTIP)(Ti(O——CH(CH₃)₂)₄) together with oxygen and one or more inert gases (Ar,He), and a TiO_(x) layer 4 deposited. In addition hexamethyidisiloxane(HMDSO) can be introduced into the plasma process so as to give a ratioof the two metal oxides in the base layer of 2:1.

-   Power (pulsed/continuous): 600-3500 W hyperfrequency (2.45 GHz)-   Process pressure: 10 μbar-0. 1 bar Process gases: Ar/He as carrier    gas through (Ti(O——CH(CH₃)₂)₄) at 50° C., Ar/he and O₂.    Top Layer 4 Comprising TiO₂ or TiO₂ Doped with Fe₂O₃:

Then on the base layer 3, after the titanium-containing process gases,as a carrier gas a small quantity of an iron-containing monomer gas isintroduced into the reaction chamber (e.g. iron-acetylacetonate complexFe(C₅H₇O₂)₃, with oxygen and one or more inert gases (Ar, He etc), todeposit an anatase-containing TiO₂ top layer 4 doped with 0.1-9 at %Fe₂O₃. At the same time by varying the process parameters, the layerstructure can be modified.

Using numerous energy-rich plasma-activated discharges from lowfrequency up to hyperfrequency range and combinations thereof it ispossible to produce the composite materials described. Examples are(Remote) AP-PECVD (atmospheric pressure plasma-enhanced chemical vapourdeposition), APNEP (atmospheric pressure non-equilibrium plasma), plasmajet, plasma broad beam burner, microwave discharge, pulsing surfacedischarge, DBD (dielectric barrier discharge), APGD (atmosphericpressure glow discharge).

Example 3 Electrically Conductive TiO_(x) Intermediate Layer 5

An electrically conductive intermediate layer 5 is produced which ismore conductive than the base layer 3 and/or the additional base layer7. The TiO_(x) layer (0.7≦x<1.5) is deposited with any substrate 1fitted with a base layer 3, in that in a reactive sputtering processless oxygen gas is supplied to the process than in the base layer 3 andthe process pressure is adapted. It is also possible to deposit theTiO_(x) layer non-reactively in a sputtering process using acorresponding target (TiO, Ti₂O₃, Ti₃O₂ etc.).

Reactive DC Sputtering Process to Obtain a TiO_(1.0) Layer with anElectrical Resistance of 1.2.10⁻² Ωcm or 50 Ωcm:

-   Target: Titanium metal (99.98%)-   Power: 3 W/cm² DC-   Process pressure: 20 μbar or 7 μbar-   Partial pressure p(O₂)/p(tot): 5% or 7.5%

1. Process for deposition on a substrate (1) of a titanium oxide layer(2), with a chemical, physical, mechanical, catalytic, and/or opticalfunction characterized in that first reactively or non-reactively a baselayer (3) is deposited of TiO_(x) with an oxygen content of 0.7≦x<2,then by increasing the oxygen content, process pressure, power and/orsubstrate temperature a top layer (4) is deposited of an amorphous orcrystalline TiO₂.
 2. Process for deposition on a substrate (1) of atitanium oxide layer (2), with a chemical, physical, mechanical,catalytic, and/or optical function characterized in that firstreactively or non-reactively a base layer (3) is deposited ofTiO_(x)(OH)_(y) with an oxygen content of 1.5≦x<1.9 and a hydroxidecontent of 0.2≦y<1.7, then by increasing the oxygen content, processpressure, power and/or substrate temperature a top layer (4) isdeposited of an amorphous or crystalline TiO₂.
 3. Process according toclaim 1, characterized in that the substrate (1) comprises highlyflammable and/or heat sensitive materials of polymers, polymer-like ornatural materials.
 4. Process according to claim 1, characterized inthat a plasma enhanced deposition processes such as magnetronsputtering, spark discharge, and plasma MOCVD are used to deposit thebase layer (3) and/or the top layer (4) on a not heated substrate. 5.Process according to claim 1, characterized in that the base layer (3)is applied after a plasma activation of the substrate (1).
 6. Processaccording to claim 1, characterized in that the base layer (3) isapplied after the deposition of a protective layer of at least one metaloxide of the group which preferably comprises MgO, ZnO, ZrO₂, In₂O₃,Sb₂O₃, Al₂O₃, and SiO₂, and/or a polar adhesion layer and anadhesion-promotion layer.
 7. Process according to claim 1, characterizedin that between the base layer (3) and the top layer (4) of the titaniumoxide layer (2) is deposited an electrically conductive intermediatelayer which preferably comprises TiO_(x) with an oxygen content of0.5≦x≦1.5.
 8. Process according to claim 1, characterized in that theprocess is performed at a substrate temperature ≦200° C. or onnot-heated substrates.
 9. Process according to claim 1, characterized inthat the base layer (3) has a total layer thickness of 3 to 1000 nmwhere the top layer (4) has a thickness in the range 10 to 50% of thetotal layer thickness (2) and that at least the nine top atomic layer(4) mainly comprise the TiO₂ modification anatase.
 10. Method of using asubstrate (1) treated using the process according to claim 1, comprisingutilizing the substrate as active hygiene protection for the preparationof drinking water, watery solutions and air, for textiles, curtains,carpets, films, membranes, cables, packaging, glassware, windows,composite materials, elements in medical technology, photovoltaic's, andoptical systems, gas sensors and electronic circuits.
 11. Method ofusing a substrate (1) treated using the process according to claim 1,comprising utilizing the substrate as active hygiene protection forhighly flammable and/or heat-sensitive materials such as polymers, lowmelting metals, composites, and natural substances in the form of rigidto flexible films, fabrics, membranes, fibres, tubes, containers, andpowders.
 12. Method of using a plastic substrate (1) treated using theprocess according to claim 1, comprising utilizing the substrate toincrease the thermal stability and flame inhibition of polymer materialsin the form of films, membranes, fibres, powders, textiles, fabrics,tubes, and containers.
 13. Method of using a substrate (1) treated usingthe process according to claim 1, comprising utilizing the substrate toincrease the thermal stability and flame inhibition of polymers, lowmelting metals, composites, and natural substances in the form of rigidto flexible films, fabrics, membranes, fibres, tubes, containers, andpowders.
 14. Process according to claim 2, characterized in that thesubstrate (1) comprises highly flammable and/or heat sensitive materialsof polymers, polymer-like or natural materials.
 15. Process according toclaim 2, characterized in that a plasma enhanced deposition processessuch as magnetron sputtering, spark discharge, and plasma MOCVD are usedto deposit the base layer (3) and/or the top layer (4) on a not heatedsubstrate.
 16. Process according to claim 2, characterized in that thebase layer (3) is applied after a plasma activation of the substrate(1).
 17. Process according to claim 2, characterized in that the baselayer (3) is applied after the deposition of a protective layer of atleast one metal oxide of the group which preferably comprises MgO, ZnO,ZrO₂, In₂O₃, Sb₂O₃, Al₂O₃, and SiO₂, and/or a polar adhesion layer andan adhesion-promotion layer.
 18. Process according to claim 2,characterized in that between the base layer (3) and the top layer (4)of the titanium oxide layer (2) is deposited an electrically conductiveintermediate layer which preferably comprises TiO_(x) with an oxygencontent of 0.5≦x≦1.5.
 19. Process according to claim 2, characterized inthat the process is performed at a substrate temperature ≦200° C or onnot-heated substrates.
 20. Process according to claim 2, characterizedin that the base layer (3) has a total layer thickness of 3 to 1000 nm,preferably 10 to 200 nm, where the top layer (4) has a thickness in therange 10 to 50% of the total layer thickness (2) and that at least thenine top atomic layer (4) mainly comprise the TiO₂ modification anatase.21. Method of using a substrate (1) treated using the process accordingto claim 2, comprising utilizing the substrate as active hygieneprotection for the preparation of drinking water, watery solutions andair, for textiles, curtains, carpets, films, membranes, cables,packaging, glassware, windows, composite materials, elements in medicaltechnology, photovoltaic's, and optical systems, gas sensors andelectronic circuits.
 22. Method of using a substrate (1) treated usingthe process according to claim 2, comprising utilizing the substrate asactive hygiene protection for in particular highly flammable and/orheat-sensitive materials such as polymers, low melting metals,composites, and natural substances in the form of rigid to flexiblefilms, fabrics, membranes, fibres, tubes, containers, and powders. 23.Method of using a plastic substrate (1) treated using the processaccording to claim 2, comprising utilizing the substrate to increase thethermal stability and flame inhibition of polymer materials in the formof films, membranes, fibres, powders, textiles, fabrics, tubes, andcontainers.
 24. Method of using a substrate (1) treated using theprocess according to claim 2, comprising utilizing the substrate toincrease the thermal stability and flame inhibition of polymers, lowmelting metals, composites, and natural substances in the form of rigidto flexible films, fabrics, membranes, fibres, tubes, containers, andpowders.
 25. Method of using a substrate (1) treated using the processaccording to claim 9, comprising utilizing the substrate as activehygiene protection for the preparation of drinking water, waterysolutions and air, for textiles, curtains, carpets, films, membranes,cables, packaging, glassware, windows, composite materials, elements inmedical technology, photovoltaic's, and optical systems, gas sensors andelectronic circuits.
 26. Method of using a substrate (1) treated usingthe process according to claim 9, comprising utilizing the substrate asactive hygiene protection for in particular highly flammable and/orheat-sensitive materials such as polymers, low melting metals,composites, and natural substances in the form of rigid to flexiblefilms, fabrics, membranes, fibres, tubes, containers, and powders. 27.Process according to claim 1, characterized in that the base layer (3)has a total layer thickness of 10 to 200 nm, where the top layer (4) hasa thickness in the range 10 to 50% of the total layer thickness (2) andthat at least the nine top atomic layer (4) mainly comprise the TiO₂modification anatase.
 28. Process according to claim 2, characterized inthat the base layer (3) has a total layer thickness of 10 to 200 nm,where the top layer (4) has a thickness in the range 10 to 50% of thetotal layer thickness (2) and that at least the nine top atomic layer(4) mainly comprise the TiO₂ modification anatase.